Table of Content

31 August 2021, Volume 42 Issue 8

Previous Issue    Next Issue

Contents

Contents

2021, 42(8):  0. 

Asbtract ( )   PDF (932KB) ( )  

Related Articles | Metrics

Paper

On the Perforation Characteristics of Concrete Wall Induced by Annular Jet and Central EFP Combined Warhead

REN Siyuan , ZHANG Qingming, ZHANG Xiaowei, TIAN Zhimin

2021, 42(8):  1569-1579.  doi:10.3969/j.issn.1000-1093.2021.08.001

Asbtract ( )   PDF (10686KB) ( )  

References | Related Articles | Metrics

A combined warhead with annular jet and central explosively formed projectile (EFP), which can produce large holes on reinforced concrete wall, is designed to solve the problem of perforating large hole on the wall. To solve the problems of twisting and deflection in forming process of annular jet, the annular liner with variable wall thickness is proposed. The variable wall thickness of annular liner is realized by two eccentric circles, and the changing gradient of wall thickness is determined by eccentricity. The forming processes of annular liner with four different wall thickness gradients were analyzed through numerical simulation, and the numerical simulation of the annular jet and the central EFP combined warhead penetrating into concrete wall was carried out. The annular jet with better density also has a certain angle of expansion. The perforation capability of the combined warhead to the concrete wall was verified through test. The test results show that the combined warhead can produce a through hole with a diameter of more than 2.5 times larger than the diameter of charge caliber on the concrete wall.

Hierarchical Control-based Real-time Energy Management Strategy for Hybrid Electric Vehicles

CHEN Luming, LIAO Zili, MA Xiaojun, LIU Chunguang

2021, 42(8):  1580-1591.  doi:10.3969/j.issn.1000-1093.2021.08.002

Asbtract ( )   PDF (11955KB) ( )  

References | Related Articles | Metrics

A real-time energy management strategy based on hierarchical control is proposed for the coordinated control of multiple power sources and low fuel economy of hybrid electric vehicles (HEVs). The mathematical models of different power sources are established by analyzing the topology of whole vehicle and the component characteristics of hybrid electric system. The wavelet filter layer is used to divide the full load power into high and low parts, and the high-frequency power is allocated to power-type power sources such as supercapacitors. The low-frequency power is used as the reference input of the model predictive control (MPC) layer. The fuel economy, power battery state of charge (SOC), and DC bus voltage are the optimization items to obtain the optimal control instructions of energy-type power sources such as diesel engine-generator sets and power battery packs. Some representative simulation experiments were performed on dSPACE and RTLAB hardware-in-loop (HIL) simulation platform to verify the effectiveness of the proposed energy management strategy. The results show that, under the condition of CUEDC cycle driving, the fuel economy of the proposed hierarchical energy management strategy is increased by 13.05% compared with the energy management strategy based on fuzzy rules, and the fuel economy is improved by 5.79% compared with the energy management strategy based on a single MPC. Besides, the target power of each energy-type power source under the hierarchical energy management strategy changes more gently, while the power-type power source is involved in the power adjustment process more frequently, which proves the effectiveness of the proposed energy management strategy in improving fuel economy and exerting power source characteristics.

Transient Characteristics of Start-up Process of an Axial Flow Water-jet Propeller

ZHANG Fuyi, LU Hang, CHEN Tairan, WU Qin, HUANG Biao, WANG Guoyu

2021, 42(8):  1592-1603.  doi:10.3969/j.issn.1000-1093.2021.08.003

Asbtract ( )   PDF (15728KB) ( )  

References | Related Articles | Metrics

The propulsion performance of an axial flow water-jet propeller during start-up process is improved to study its transient characteristics and self-priming performance. The SST k-ω turbulence model, Zwart cavitation model and Free Surface model are used to study the start-up process of the proposed axial flow water-jet propeller under the framework of Reynolds-averaged Navier-Stokes equation. The effects of start-up time and waterline height on the transient characteristics of water-jet propeller were analyzed. The steady-state numerical method was verified based on the experimental data of water-jet pump, which is in good agreement with the numerical results. The results indicate that the start-up process show significant transient characteristics. The flow rate and the head reach the stable state later than the rotation speed, and the lag becomes more severe as the start-up time decreases. Cavitation occurs on the suction surface around the leading edge of the blade when the rotation speed is 0.6 times higher than the designed rotation speed. The dimensionless cavity area increases with the increase in the rotation speed. At the same rotation speed, the dimensionless cavity aera is negatively correlated with the start-up time, while the working capacity of the blade is positively correlated with the start-up time. When the waterline height is greater than or equal to 0.15 times larger than the impeller diameter with the center line of the pump shaft as zero reference line, the gas inside the water-jet propeller can be completely discharged in a short time, and the lag of flow rate and head becomes more severe as the waterline height decreases.

3-D Inner Flow Field Characteristics of Ladder-shaped Multiple Charge Rocket Motor with Erosive Burning

ZHOU Baihang， TAO Ruyi， WANG Hao， RUAN Wenjun

2021, 42(8):  1604-1612.  doi:10.3969/j.issn.1000-1093.2021.08.004

Asbtract ( )   PDF (4997KB) ( )  

References | Related Articles | Metrics

In order to study the internal flow field characteristics of ladder-shaped multiple charge rocket motor,the full 3-D internal flow field models for erosion ratio and average erosion ratio were numerically simulated using Fluent software. The secondary development was carried out through User Defined Function(UDF) interface programming. The coordinates and pressure of each node of erosion ratio model and the average pressure of each burning surface of average erosion ratio model are extracted, and the formulas of burning rate and mass flow rate are introduced to control the moving velocity of boundary grid and the mass flow rate of gas inlet per unit area. The spatial distribution information of pressures at each moment in two inner flow field models and the pressure-time curves of three monitoring points in the front, middle and rear of combustion chamber were obtained through numerical simulation. The calculated results of the two models are compared.The inner flow field and the pressure difference between the inside and outside of grain in the erosion ratio model are analyzed. The results show that the maximum pressure difference between the two models is no more than 3%, which is basically the same after the equilibrium pressure section. There is no obvious erosive burning trumpet type in the erosion ratio model during the working process of motor. The maximum pressure difference between the inside and outside of grain in the front high pressure area is not more than 3.9%, and is not more than 8%in the rear low pressure area. The pressure-time curves of the monitoring points is in good agreement with the test data.

Dynamic Stability of Spin-stabilized Projectile with Spoiler

YANG Jie， CHANG Sijiang， WEI Wei

2021, 42(8):  1613-1623.  doi:10.3969/j.issn.1000-1093.2021.08.005

Asbtract ( )   PDF (2658KB) ( )  

References | Related Articles | Metrics

The dynamic stability of spin-stabilized projectile with spoiler is analyzed to develop a new type of trajectory correction projectile. The dynamic model of the spin-stabilized projectile with spoiler is derived and simplified to obtain its non-homogeneous angular motion equation. The analytical solutions of the transient and steady-state responses of angle of attack under step excitation are obtained by using the non-homogeneous angular motion equation. The effects of structural, flight and aerodynamic parameters on the bifurcation characteristics and stability of the system are analyzed based on the nonlinear angular motion equation. The correction ability of the spin-stabilized projectile with spoiler was analyzed by numerical calculation. The results show that the analytical solution of the angle of attack has high accuracy, the aerodynamic parameters have a great influence on the stability region of the equilibrium point of the dynamic system, and the control efficiency of the spoiler is very high.

Characteristics of Muzzle Flow Field of Large Caliber Gun Considering Chemical Reaction

WANG Danyu, NAN Fengqiang, LIAO Xin, XIAO Zhongliang, DU Ping, WANG Binbin

2021, 42(8):  1624-1630.  doi:10.3969/j.issn.1000-1093.2021.08.006

Asbtract ( )   PDF (3631KB) ( )  

References | Related Articles | Metrics

The strong blast wave and muzzle flash generated during launching may damage the perssonnel or equipment and expose the launching position since large-caliber gun has complicated charging elements and a large amount of charge. The launch process of a 155 mm gun is simulated to study the characteristics of conditions of muzzle flow field, such as the formation of muzzle flash. A chemical reaction model is proposed, in which the characteristics of high speed, high pressure, high temperature and complex chemical reactions with environment during launching are considered. And also the Reynolds averaged Navier-Stokes equation and k-ε turbulence model are established by taking into account the small disturbance of projectile and barrel wall. The formation and evolution process of muzzle field after a projectile is discharged from the muzzle without considering the initial flow field are simulated and analyzed based on the established muzzle flow field model. The results of numerical analysis clearly show the complex wave system structures such as Mach disk, blast wave, and the generation of muzzle flash, especially the secondary flash. The results show that the calculated shape and size of fireball are in good agreement with the experimental results, and the error between the calculated and experimental results is no more than 8%.

Preparation of HMX/Al Composite Particles with “Surface Embedded and Inner Coated” Microstructure bySpray Coating and Its Applied Performance

FENG Xiaojun， XUE Lexing， FENG Bo， PAN Wen

2021, 42(8):  1631-1637.  doi:10.3969/j.issn.1000-1093.2021.08.007

Asbtract ( )   PDF (3815KB) ( )  

References | Related Articles | Metrics

In order to improve kinetics conditions of aluminum during detonation, HMX/Al composite particles were prepared by spray coating method, and aluminized explosives containing the particles were prepared. The morphologies and surface element composition of composite particles were characterized by scanning electron microscopy (SEM) and energy dispersive spectrum (EDS), and the chemistry structure was analyzed by infrared spectroscopy (IR). Explosion performance of HMX/Al composite-based aluminized explosive were estimated through the test of mechanical sensitivity, detonation heat, metal driving and explosion chamber. Results show that the optimized preparation conditions of “surface embedded and inner coated” microstructure are powdered aluminum with particle size of 13 μm without F2603 pre-coating and ester pre-cleaning. The connection of composite particles between HMX and Al is formed by non-bonding. The preparation process has no significant effect on impact sensitivity of composite particles, while the friction sensitivity of HMX/Al composite particles with “surface embedded and inner coated” microstructure is significantly reduced from 88% to 12%. Detonation heat, maximum speed of metal-driving flyer and afterburning maximum temperature of composite particles-based aluminized explosives are 5.5%, 7.3% and 6.4% higher than those of traditional samples, respectively. This indicates that the HMX/Al composite particles can be used to make the aluminum powder participate in detonation reaction in advance and improve its reaction completeness.

Reinforcement Learning-based Intelligent Guidance Law for Cooperative Attack of Multiple Missiles

CHEN Zhongyuan, WEI Wenshu, CHEN Wanchun

2021, 42(8):  1638-1647.  doi:10.3969/j.issn.1000-1093.2021.08.008

Asbtract ( )   PDF (2627KB) ( )  

References | Related Articles | Metrics

A reinforcement learning-based cooperative guidance law utlitizing a deep deterministic policy gradient descent neural network is proposed to achieve the cooperative attack of multiple missiles against a target and improve the attack effectiveness. The estimation equation of time-to-go based on the linear engagement dynamics is revised to improve the estimation accuracy of time-to-go, which is no longer restricted by the assumption of small angle. The time-to-go error of each missile is regarded as the coordination variable. The time-to-go error and range-to-go of each missile are used as the observables of the reinforcement learning algorithm. The reward function is constructed by using miss distance and time-to-go error, and then a reinforcement learning agent is generated by offline training. In the process of closed-loop guidance, the reinforcement learning agent generates guidance commands in real time, by that simultaneous attack can be achieved. Simulated results verify that the proposed reinforcement learning guidance law can achieve simultaneous attack on the target. Compared with the traditional cooperative guidance law, the reinforcement learning cooperative guidance law can be used to obtain smaller miss distances and smaller attack time errors.

Influence of Rectifying Wedge on the Flow Structure and Aerodynamic Heating Environment around All-movable Rudder

TAN Meijing， YANG Guang， LI Yu， ZHOU Yu， CAO Zhanwei， YAN Hao， TAN Zijing

2021, 42(8):  1648-1659.  doi:10.3969/j.issn.1000-1093.2021.08.009

Asbtract ( )   PDF (16046KB) ( )  

References | Related Articles | Metrics

The aerodynamic heating around aerodynamic rudder by local-configuration optimization is reduced to effectively enhance the livability and adaptability of high-Mach-number flight vehicle. The rectifying wedge is an effective means for optimizing the flow and aerodynamic heating characteristics for high Mach number flight vehicle. A numerical method is proposed to investigate the flow and aero-heating characteristics under a configuration of high-Mach-number plate/rudder. The proposed numerical method was used to study the influence of rectifying wedge on the flow structure and aerodynamic heating environment around all-movable rudder and validated through thermal measurement test in shock wave tunnel. The results show that the usage of rectifying wedge contributes to the reduction in both flow speed and aero-heating capability. This could attribute to the reduction effect of rectifying wedge shock wave on flow speed by the speedily expand and separation. Moreover, the aerodynamic heating environment around all-movable rudder within the span width region is found lower with rectifying wedge in general. With the decrease in rectifying wedge angle, all-movable rudder heating environment gets worse. Meanwhile, with the increase in span width, all-movable rudder heating environment gets better.

Fluid-structure Coupling Simulation Method for the Opening Process of Fragile Front Cover of Canister Launcher

ZHANG Baozhen, WANG Hanping, DOU Jianzhong, CHENG Mengwen

2021, 42(8):  1660-1669.  doi:10.3969/j.issn.1000-1093.2021.08.010

Asbtract ( )   PDF (9750KB) ( )  

References | Related Articles | Metrics

The opening process of fragile front cover of canister launcher in the pressure wave is a typical fluid-structure interaction problem. In order to study this opening process, the static tensile and compression test，and the dynamic tensile and compression test are carried out on the polyurethane composite material of fragile front cover，respectively. The subroutine VUSDFLD is used to expand the concrete damage plasticity (CDP) constitutive model to describe the loading and cracking conditions of the fragile front cover. Based on the computational fluid dynamics (CFD) simulation results of the flow field in the canister launcher, an Euler’s method-based model of the same case is built and verified, and the opening process of the fragile front cover is simulated by the coupled Eulerian-Lagrangian (CEL) algorithm. It shows that the simulated results based on the developed CDP model are in good agreement with the experimental data; and the simulation method combining CFD and CEL algorithms can effectively solve the fluid-structure interaction problem of opening process of fragile front cover and has higher accuracy.

A Co-channel Interference Suppression Algorithm for LTE-based Passive Radar

SHAO Xiaolang， HU Taiyang， XIAO Zelong， WEI Yongping， WANG Hua

2021, 42(8):  1670-1679.  doi:10.3969/j.issn.1000-1093.2021.08.011

Asbtract ( )   PDF (4580KB) ( )  

References | Related Articles | Metrics

The traditional co-channel interference suppression algorithms of LTE （long-term evolution）-based passive radar adopt the strategy of cancelling or suppressing the co-channel interference. They are widely used and can be applied to various illuminators of opportunity external radiation source radar. However, there are few studies on co-channel interference suppression by utilizing the characteristics of LTE signal. A co-channel interference suppression algorithm, which combines the sources separation technique and characteristics of LTE signal, is proposed. The proposed algorithm is used to estimate the direction of arrival of incident signals, obtain the mixing matrix, and separate the signals based on the least square method. Then the parallel cross-ambiguity correlation of the separated source signals is executed. The differences among the LTE main base station signal, the co-channel interference and the target echo in the distance-Doppler domain are used to identify the target. Simulated results show that the proposed algorithm has better suppression performance compared to the traditional co-channel interference suppression algorithms, and avoids the traditional clutter cancellation process. Meanwhile, the extra time assumption caused by multiple calculations of cross-ambiguity correlation can be reduced by means of parallel operation.

Radar Emitter Signal Recognition Based on Convolutional Neural Network and Coordinate Transformation of AmbiguityFunction Main Ridge

PU Yunwei， LIU Taotao， GUO Jiang， WU Haixiao

2021, 42(8):  1680-1689.  doi:10.3969/j.issn.1000-1093.2021.08.012

Asbtract ( )   PDF (5662KB) ( )  

References | Related Articles | Metrics

For the time-consuming and inconspicuous features of artificially extracting radar emitter signal features，a recognition method based on deep learning convolutional neural network and coordinate transformation of ambiguity function main ridge is proposed. The proposed method is used to extract the main ridge of ambiguity function of signal through fast discrete fractional Fourier transform，and then take the two-dimensional time-frequency image of polar coordinate domain of ambiguity function main ridge as the input of the convolutional neural network to realize the sorting and recognition of different radar signals. Simulation experimental results show that the proposed method not only maintains 100% recognition rate above 0 dB，but also stabilizes the recognition accuracy rate above 90% at -6 dB. Compared with traditional radar signal recognition methods and other deep learning-based recognition methods，the proposed method has greatly improved recognition rate and robustness，and has certain engineering application value.

Markov Evolutionary Game Model and Migration Strategies for Multi-stage Platform Dynamic Defense

WANG Gang, WANG Zhiyi, ZHANG Enning, MA Runnian, CHEN Tongrui

2021, 42(8):  1690-1697.  doi:10.3969/j.issn.1000-1093.2021.08.013

Asbtract ( )   PDF (1236KB) ( )  

References | Related Articles | Metrics

Markov evolutionary game model and migration strategy of multi-stage platform dynamic defense are proposed to improve the efficiency of platform dynamic defense under persistent and periodic attacks. The cyclical and phased characteristics of platform dynamic defense are analyzed from the network attack and defense principle of platform dynamic defense, and the key parameters and revenue of multi-stage platform dynamic defense are calculated. Markov evolutionary game model of multi-stage platform dynamic defense is established. According to the stage of the game, the discount factor and transfer probability are introduced into the total revenue calculation. On this basis, the existence of Nash equilibrium in multi-stage Markov platform dynamic defense evolutionary game is studied, and the Nash equilibrium solution and optimal migration strategy selection algorithm are given. Finally, an example is given to design the analysis process of the migration strategy, and the effectiveness of the proposed model and migration strategy is verified by simulation.

An Improved YOLOv3 Model for Arbitrary-oriented Ship Detection in SAR Image

XU Ying， GU Yu， PENG Dongliang， LIU Jun， CHEN Huajie

2021, 42(8):  1698-1707.  doi:10.3969/j.issn.1000-1093.2021.08.014

Asbtract ( )   PDF (7258KB) ( )  

References | Related Articles | Metrics

An improved YOLOv3 model for arbitrary-oriented ship detection is proposed to realize the simultaneous output of both position and aspect angle estimation information for synthetic aperture radar (SAR) ship detection. The scope of target’s aspect angle which is beneficial for the stability of model parameter regression is defined, and the multi-task loss function is defined based on the predictions of both vertical and rotated bounding boxes. The combinations of prediction results of both vertical and rotated bounding boxes are used to rectify target’s aspect angle estimation for improving the detection performance. The SAR ship detection dataset plus (SSDD+) and high resolution SAR images dataset (HRSID) are used to do performance and transferability tests for the proposed model. The experimental results demonstrate that, for SSDD+dataset, the mean average precision reaches 0.841 when intersection over union equals 0.5 (mAP_0.5); mAP_0.5 can reach 0.530 when HRSID is used to perform transferability tests; the proposed model takes about 25 milliseconds to process one frame when the input resolution of the model is 416×416. High resolution ship collection 2016 (HRSC2016) which is a visual ship recognition dataset is also used to verify the adaptability of the proposed model, and mAP_0.5 reaches 0.888, which is superior to some known models. The proposed model can be applied to detect SAR ships in pure sea background, and can meet real-time requirement of ship detection.

Influence of Wire Grating on Horizontally Polarized Radiated-wave Simulator with Biconical-wire Grating Structure

XIAO Jing, WU Gang, XIE Linshen, WANG Haiyang, SUN Chuyu

2021, 42(8):  1708-1715.  doi:10.3969/j.issn.1000-1093.2021.08.015

Asbtract ( )   PDF (2991KB) ( )  

References | Related Articles | Metrics

The effects of wire density and width of wire grating antenna on the radiation characteristics of horizontally polarized radiated-wave antenna with biconical-wire grating structure are studied through electromagnetic simulation. The 3D electromagnetic simulation software is applied to build a model of biconical-wire grating antenna. In the cases of the same parameters of pulse source and excitation, the wire number of each wire plate is set to 24, 48, 96 and 192 to study the operational principle of wire plate antenna with different densities. The radius of wire is varied from 1 mm to 40 mm to analyze its effect on the radiation field. The experimental area of the simulator is estimated. It shows that the measuring points right below the bicone center are basically unaffected by wire density and width, while at other measuring points, the wire density has an effect on the leading edge and peak value of the polarization component. Generally, larger wire density will cause smaller leading edge and peak value. When the wire number is increased from 24 to 192, the peak value and leading edge changes about 5% and 10%, respectively. But the changing rate of peak value gradually decreases with the increase in wire number. When wire number exceeds 96, the peak value is basically unchanged. The influence of wire width on radiation field can be ignored. Experimental result shows that the simulator experimental area at 4 m above the ground is a rectangle with the size of 12 m×16 m.

An Image Deniosing Algorithm Based on Fast Non-local Mean and Super-resolution Reconstruction

LI Jing, LIU Zhe, HUANG Wenzhun

2021, 42(8):  1716-1727.  doi:10.3969/j.issn.1000-1093.2021.08.016

Asbtract ( )   PDF (13140KB) ( )  

References | Related Articles | Metrics

Most of the existing image denoising algorithms can only deal with the noise intensity varying in a limited range. For the actual image noise intensity varying in a wide range, an image denoising algorithm is proposed based on the fast non-local means algorithm and the deep residual convolutional network-based super-resolution reconstruction algorithm. The improved non-local means algorithm and Box filter are used to denoise the image initially, and then the initial denoised image is reconstructed with end-to-end super-resolution of low-resolution images by the deep residual convolutional network. The simulated results show that the proposed algorithm can be used to obtain higher peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) compared with other classical denoising algorithms when the noise intensities are 15, 25, 40, 50 and 60. And with the increase in noise intensity, its advantage is more and more obvious. The proposed algorithm is suitable for denoising of known noise and blind noise. And the proposed algorithm is superior to the classical noise reduction algorithms in blind noise reduction. In addition, the proposed algorithm can restore the image details better and generate a better visual effect.

Evolution Properties of Tail Cavity Oscillation of Underwater Launched Vehicle

QUAN Xiaobo， YOU Tianqing， ZHANG Chenxing， WANG Fanyu， KONG Decai

2021, 42(8):  1728-1734.  doi:10.3969/j.issn.1000-1093.2021.08.017

Asbtract ( )   PDF (2310KB) ( )  

References | Related Articles | Metrics

In order to investigate the evolution characteristic of tail cavity formed by underwater vertical launch vehicle, as well as the influence of tail cavity on the hydrodynamics and upstream flow of the vehicle, an axisymmetric boundary element code based on potential flow theory was developed to analyze the transient flow field of vehicle with tail cavity. A numerical simulation was performed. The simulated results show that the oscillation of tail cavity has a significant influence on the upstream pressure, the drag force on wet surface and the upstream nose cavity. The oscillation of tail cavity can cause the upstream surface pressure to superimpose a certain amplitude of pressure fluctuations while dropping with the environmental static pressure. The pressure fluctuations are approximately exponentially distributed in space. The closer the position is from the tail cavitation, the greater the pressure fluctuation is. The oscillation of tail cavity makes the resistance of the wetted area of the vehicle show a trend of gradual increase during the oscillation; the oscillation of tail cavity can cause a slower evolution speed of shoulder cavity than that in the non-oscillation state, and the pressure inside the cavity and the peak end retroreflective pressure are larger.

A Near-field Acoustic Image Measurement Method Based on Compressed Sensing in Complex Domain

CHEN Xinhua, ZHENG Enming, LI Yi, YANG He, ZHOU Quanbin

2021, 42(8):  1735-1743.  doi:10.3969/j.issn.1000-1093.2021.08.018

Asbtract ( )   PDF (4876KB) ( )  

References | Related Articles | Metrics

In order to solve the performance degradation problem of near-field acoustic image measurement method based on compressed sensing in frequency domain, the time delay compensation and correlation are processed based on the relationship between phase shift and time delay in array signal processing according to the near-field scanning position in the complex domain. A near-field acoustic image measurement model of sensing matrix in complex domain is established. Taking the numerical simulation data and the data measured in a near-field target location experiment as an example, the processed results of the proposed model and the frequency domain compressed sensing model are compared. The results show that, compared with frequency domain compressed sensing, the tolerance of lowest signal-to-noise ratio of this method is improved nearly 10lgM dB (where M is the channel number of array) by changing the construction way of sensing matrix and observation sequence, and the ability of near-field acoustic image measurement is improved.

Optimal Design of Pressure-resistant Spherical Shell for Co-vibrating Vector Hydrophone

WANG Chao， WANG Wenlong， SUN Qindong， SUN Wenqi

2021, 42(8):  1744-1752.  doi:10.3969/j.issn.1000-1093.2021.08.019

Asbtract ( )   PDF (6623KB) ( )  

References | Related Articles | Metrics

For the structural pressure resistance problem of deep-water vector hydrophones, the formula of maximum stress of spherical shell under external pressure was derived, and the influences of material, radius and thickness of co-vibrating spherical vector hydrophone on its acoustic performance and pressure-resistance were analyzed. Based on this, a design method of thin pressure-resistant spherical shell with minimum average density was given. The applicability of several commonly used deep sea engineering materials was studied, and a co-vibrating spherical vector hydrophone with working depth of 3 000 m was designed and developed by using 7075T6 aluminum alloy. The finite element simulation of vector hydrophone was carried out, and the sensitivity, directivity and pressure-resistance were tested experimentally. Results show that the vector hydrophone provides well cosine directivity and has a sensitivity of -188 dB at 500 Hz and a pressure resistance of 37.5 MPa, and the design method of thin pressure-resistant spherical shell with minimum average density and the engineering prototype design scheme are reasonable and practicable.

Damage Response Characteristics of UHMWPE/aluminum Foam Composite Sandwich Panel Subjected to CombinedBlast and Fragment Loadings

CHENG Yuansheng， XIE Jieke， LI Zhe， LIU Jun， ZHANG Pan

2021, 42(8):  1753-1762.  doi:10.3969/j.issn.1000-1093.2021.08.020

Asbtract ( )   PDF (5670KB) ( )  

References | Related Articles | Metrics

A novel composite sandwich panel with UHMWPE and aluminum foam cores is proposed. The damage mechanism of composite sandwich panel under the combined blast and fragment loading is studied by using LS-DYNA software. The synergetic effects of blast and fragment loadings were achieved by attaching the pre-fabricated fragments to the bottom surface of the cylindrical TNT explosive. The proposed numerical model was validated by comparing the simulated results with the existed experimental data. Based on the calibrated numerical model, the whole dynamic response process, velocity and acceleration response at feature point, as well as the energy dissipation characteristics for the composite sandwich panel were analyzed in detail. Further attention was paid to the effect of face-sheet thickness on the failure modes and plastic deformation of panel. The numerical results reveal that there are two evident peaks in the acceleration-time curve of the fragment and front face-sheet center, which are caused due to the impact of fragments on the front face-sheet and UHMWPE core. The front face-sheet and aluminum foam core contribute to most of the energy absorption. For the target panel with equal face-sheet thickness, a superior blast performance is achieved by well balancing between the penetration resistance of front face-sheet and the bending stiffness of back face-sheet.

Detection Method for Chamber of Large-caliber Artillery Barrel Based on Electromagnetic Ultrasonic Surface SH-wave

ZHANG Jin， WANG Xuebin， SHI Wenze， DONG Zihua， DENG Haifei

2021, 42(8):  1763-1770.  doi:10.3969/j.issn.1000-1093.2021.08.021

Asbtract ( )   PDF (6577KB) ( )  

References | Related Articles | Metrics

The inner bore surface of a large-caliber artillery barrel with drug chamber must be subjected to high temperature and pressure during the launching process. This may produce multi-network cracks and pose a hidden danger to safety and performance. The challenge remains that the traditional detection methods have higher requirements for inner wall cleanliness while the detection period takes a long time. A detection method based on electromagnetic acoustic transducer surface shear-horizontal(SH) wave is proposed to detect the cracks on the inner bore surface of a gun barrel with chamber. Quantitative detection is also carried out in assessing defects. This process includes establishing a finite element model relating to the radiated sound field of surface SH wave on permanent periodic magnet electromagnetic acoustic transducer(EMAT). The influences of length and pair number of permanent magnet on the radiated sound field are analyzed, and the design parameters of EMAT are optimized. In studying the characteristics of surface SH wave sound fields, a finite element model of the surface SH wave propagation in a gun barrel with the chamber with cross cracks was also established. The law of interaction relating to the surface SH wave and crack defects with different angles were verified through both study and experiment. The results illustrate that the electromagnetic acoustic transducer composed of 12 pairs of permanent magnets with length of 20 mm could be used to detect the cross cracks with 10 mm×1 mm×2 mm, and analyze the influence law of crack angle and echo amplitude.

Modeling and Optimization of Weapon-target Assignment for Group Targets Defense Based on NSGA-Ⅲ Algorithm

NIE Junfeng, CHEN Xingjun, SU Qi

2021, 42(8):  1771-1779.  doi:10.3969/j.issn.1000-1093.2021.08.022

Asbtract ( )   PDF (3129KB) ( )  

References | Related Articles | Metrics

As an important part of the task planning of group targets defense, the modeling and optimization of weapon-target assignment are of great significance to improve the defense effect and ensure the quality of task completion. In view of a basic trend that the defense strategy changes from the traditional point-to-point saturation attack to a reasonable firepower coverage, a weapon-group targets assignment model is established by considering the effects of damage threshold, total weapon resources and 0-1 integer constraints. The proposed model is based on the principles of maximum attack effectiveness, its own maximum surplus value and minimum weapon consumption. The optimization framework of weapon-group targets assignment based on NSGA-Ⅲ is proposed, and the specific optimization process of the algorithm is given. The simulation of combat mission is realized, and the convergence metric and spacing metric are used to compare the performances of NSGA-Ⅲ, SPEA2 and NSGA-Ⅱ. The simulated results demonstrate that NSGA-Ⅲ has better performance, which can effectively solve the weapon-target assignment modeling and optimization problem of group targets defense.

A Collocation Scheme of Distributed Cooperative Operational Weapons Based on OODA Loop

CHEN Qinglin, TIAN Hongtang, WANG Peng, LENG Shuxiang, XIAO Zuolin

2021, 42(8):  1780-1788.  doi:10.3969/j.issn.1000-1093.2021.08.023

Asbtract ( )   PDF (3301KB) ( )  

References | Related Articles | Metrics

An optimization method for the collocation scheme of distributed cooperative operational weapons under different operational conditions is studied based on the comprehensive combat effectiveness and the OODA Loop model. An index system of distributed cooperative operational effectiveness is established, and the underlying operational capability is calculated based on index method. The operational capabilities involved in OODA Loop are analyzed to establish the operational effectiveness evaluation model of every single link. A comprehensive effectiveness evaluation model of the equipment system and an integer programming model for the collocation scheme of weapons are established considering the effectiveness of OODA Loop and its anti-destruction capability. Finally, combining with an example, the optimal collocation scheme of the equipment for performing the reconnaissance mission and the reconnaissance-attacking mission is studied, which proves the feasibility and effectiveness of this method.

Comprehensive Review

Review on Performance Evaluation of Solid Rocket Motors with Charge Defects

GAO Feng, ZHANG Ze

2021, 42(8):  1789-1802.  doi:10.3969/j.issn.1000-1093.2021.08.024

Asbtract ( )   PDF (1474KB) ( )  

References | Related Articles | Metrics

The charge defect is an important factor affecting the safe work of solid rocket motors (SRM). In order to ensure safe launch, the deviation of the SRM performance caused by the charge defects needs to be analyzed to evaluate the working performance of SRM. In view of the complexity of the behavior of charge defects, a complete evaluation system has not been established. For the behavior of SRM charge defects, the theoretical and experimental research methods of crack and debonding propagation are reviewed, including the research on the crack initiation criterion, the factors affecting the growth and the fracture performance of propellant material. The research status of the interaction mechanism between grain crack and gas is reviewed from two aspects: the boundary conditions of gas entering the crack and the influence of gas propagation on the crack propagation. In order to achieve the purpose of numerical simulation of complete working process of SRM with charge defects, the research on its numerical calculation methods is summarized and analyzed from combustion surface regression calculation method, fluid-heat-solid coupling calculation method and defect propagation calculation method. The numerical index of the working performance of SRM with charge defects is expected to be obtained, which will be used as a reference for performance evaluation of SRM with charge defects. Finally, the development in the research on the behavior of charge defects and numerical calculation methods is prospected.

Research Notes

Measurement of Piston Motion of Two-stage Gas Gun Based on Strain Gauge Measuring System

ZHAO Qifeng， LI Yunliang， LI Jin， ZHANG Xiangrong， ZHU Yurong， TAN Shushun, ZHANG Zidong

2021, 42(8):  1803-1808.  doi:10.3969/j.issn.1000-1093.2021.08.025

Asbtract ( )   PDF (2352KB) ( )  

References | Related Articles | Metrics

In order to study the motion process of piston in the interior ballistics of two-stage light gas gun,the piston motion is measured using a strain guage measuring system.The measuring points of strain gauge were laied at a certain distance for the external wall of pump tube of 57 mm/10 mm two-stage light gas gun, and the ring strain of the pump tube caused by piston motion was monitored and measured during the launch of the light gas gun. The change of internal ballistic pressure in the process of piston motion under typical experimental conditions was obtained directly. The piston motion time history and the relationship between displacement and bottom pressure were derived. The results show that the relationship between piston velocity and displacement is in good agreement with the theoretical results, and the feasibility of the proposed method is verified. It provides theoretical guidance for optimizing the program parameters of the internal ballistic of the light gas gun and improving the launching performance of the two-stage light gas gun.